1. Field of the Invention
The present invention provides an improved optical scanner for use on programmable phonograph record players such as that shown and described in copending patent applications Ser. No. 682,079, filed Apr. 30, 1976, and Ser. No. 705,138, filed July 14, 1976, which are assigned to the assignee of the present invention. In particular, the invention relates to a scanner masking system which increases the performance of the optical scanner.
2. Brief Description of the Prior Art
The above copending U.S. Patent Applications are incorporated herein by reference and show various phonograph devices which are designed to permit a user to select a certain number of sound tracks to be played from a particular record while skipping certain other sound tracks. In such programmable phonograph devices, an optical scanner assembly is provided to detect the presence of an approaching land area between modulated or recorded grooved sound track portions on a record. In order to provide accurate and reliable sensor readings, it is desirable that the light emitter be directed to a limited area on the record surface for reflection to the photodetector to increase performance in the recognition of very narrow land area widths and also very narrow modulated sound track portions.